Spray nozzle

ABSTRACT

An airless spray nozzle particularly adapted for coating the interior cylindrical surface of objects such as metal cans for food, beverages and other substances which need protection against injurious reaction with or pollution from contact with the material of the can. The nozzle has an orifice that produces a spray having an asymmetrical fan-shaped pattern so that the flow can be matched to the internal surface configuration of a can or similar cylindrical object to apply a uniform coating thereto.

United States Patent 1 Stumphauzer et al.

[ 1 June 5,1973

[54] SPRAY NOZZLE [75] Inventors: William C. Stumphauzer, Sheffield Lake, Ohio; Edwin F. Hogstrom, Manchester, Mo.; Eric T. Nord, Oberlin, Ohio; Richard E. Schneider, Elyria, Ohio; Alvin A. Rood, Westlake, Ohio [73] Assignee: Nordson Ohio [22] Filed: June 8, 1972 [21] App]. No.: 261,027

Corporation, Amherst,

Related US. Application Data [62] Division of Ser. No. 13,598, Feb. 24, 1970, Pat. No.

[52] US. Cl. ..239/598, 239/601, 117/96 [51] Int. Cl. ..B44d 1/08, B05b 1/04 [58] Field of Search ..239/597599, 601 568; 117/105.1, 96; 118/302 [56] References Cited UNITED STATES PATENTS 2,619,388 11/1952 Wahlin ..239/597 2,683,626 7/1954 Wahlin ..239/599 X 2,778,687 1/1957 Hegstad ..239/60l 2,964,248 12/1960 O'Brien et al. ..239/658 X 2,971,250 2/1961 Wahlin ..239/60l X FOREIGN PATENTS OR APPLICATIONS 1,064,996 4/1967 Great Britain ..239/599 Primary ExaminerRobert S. Ward, Jr.

Attorney-Frederick M. Bosworth and Roy F.

Hollander [57] ABSTRACT An airless spray nozzle particularly adapted for coating the interior cylindrical surface of objects such as metal cans for food, beverages and other substances which need protection against injurious reaction with or pollution from contact with the material of the can. The nozzle has an orifice that produces a spray having an asymmetrical fan-shaped pattern so that the flow can be matched to the internal surface configuration of a can or similar cylindrical object to apply a uniform coating thereto.

10 Claims, 19 Drawing Figures PATENTEDJUH 5197s SHEET 10F 3 milllliiiim- PATENTEDJUH 5 I975 sum 2 BF 3 WIIIHM" SPRAY NOZZLE CROSS-REFERENCE TO RELATED APPLICATION This application is a division of applicants copending application Ser. No. 13,598 filed Feb. 24, 1970 and now U.S. Pat. No. 3,697,313.

BACKGROUND OF THE INVENTION This invention relates to airless spray nozzles and more particularly to such a nozzle particularly adapted for coating the interiors of cylindrical objects such as metal cans.

Various methods have been proposed for coating the interiors of cans used to contain food, beverages and various liquids or gases to protect the contents from contact with the can material. These methods and the corresponding means have varied to some extent depending upon the characteristics of the can to be coated. The prior practices described below are directed particularly to coating circular cylindrical cans and the nozzle of our invention is particularly suited for that and similar purposes.

In conventional practice metal cans are made in two pieces or in three pieces. In each case one piece is applied in a final operation to close and seal the can after it has been filled with food or drink. The other part of a two-piece can may be a deep drawn cylinder with a closed end. Three-piece cans, so called, comprise open ended cylindrical body shells with separate top and bottom end discs. One end disc may be coated simultaneously with the can body, as a two-piece can. The interior of the cylindrical can body is conventionally made of metal and has a seam running the length of the can. This seam may be of any common type such as a lapped seam which is soldered and crimped or cemented, or a butt seam which is welded. The bodies of three-piece cans, instead of being drawn from one piece of metal have been made as a double open end cylinder to which an end closure is fastened to seal each end, leaving a circular seam at the joint of the closure and side wall. The end closure may contain an easy open feature having a pull-tap riveted to the center of the cover.

The two or three piece cans with one closed end have heretofore been coated while being rotated about their own axes, and, using airless methods, spraying the interior of each can during a few revolutions using a single ,drumhead nozzle and projecting the spray through the open end. The outlet orifice of the prior art drumhead nozzle provided a fan-shaped spray pattern distributed so that a maximum amount of paint emerged from the orifice at one end of the fan with the amount of paint decreasing approximately linearly to a minimum amount at the other end of the fan.

A common method of gaging the distribution of flow from a particular nozzle is to spray a short burst ,of coating material against an upright, vertical substrate with the spray pattern oriented with its long axis horizontal. Typically the substrate contains alternating lands and grooves, as in a corrugated sheet, to offset the effect of adverse influences such as the blast from the spray gun which can cause wash out or distortion of the true spray pattern. Therefore, the quantity of coating material sprayed on any particular area will be reflected by the length, longer or shorter, of the rivulet in the groove running vertically downward beneath it.

A particular spray nozzle will reflect its own peculiar characteristics when gaged by the above-described method. The known drumhead nozzle has a spray pattern that is skewed heavily toward one end. The commonly used prior. art, flat fan, airless paint spray nozzle has an orifice formed symmetrically with respect to the nozzle axis and slashed with a V-notch through a substantially hemispherical dome down to about the base circle of the dome. Nozzles with such orifices give, and gave, a smoothly distributed, symmetrical spray pattern having maximum flow in the middle with gradually diminished flows tapering or feathering from the middle to the ends of the pattern. Heretofore there have been no airless spray nozzles that provided desirable asymmetrical spray patterns between the extremes of the drumhead and the symmetrical V-notch patterns.

The drumhead nozzle in prior practice was oriented with respect to the can so that the maximum flow of coating material was directed axially the length of the can and the fan-shaped pattern was directed toward the radius of the can bottom and one longitudinal line on the side wall from the bottom to the open end of the can. This procedure resulted in a substantially uniform coating being applied over the side wall of the can; the distribution of the spray fan compensating for the increasing distance the paint had to travel from the open to the closed end of the can, but the bottom of the can and the bottom circular seam received a non-uniform coating. The pattern of the drumhead nozzle is such that the place of maximum flow of paint had to be directed either at the circular seam, leaving too little material in the center of the can bottom, or the nozzle had to be directed closer to the center of the end of the can resulting in a deposit, due to centrifugal force, of excessive paint in the circular seam. The rivet required in the three-piece can with the easy open of pull tab feature, was particularly difficult or impossible to coat evenly. The only known' remedy for an inadequately coated can was to spray more than enough paint along the side and near the seam to get a desirable minimu coating on the central part of the bottom.

Spray coating the interior of the two-piece can or three-piece can with one end closed has also been accomplished in the prior art by an air atomizing or airless spray nozzle mounted on a lance that is reciprocated into and out of the can along its axis while the can is rotated. In the lancing operation the spray may be turned on either while the lance carrying the nozzle is reciprocated from its innermost position to the outside of the can, or while moving from an external position to the inside of the can, or during reciprocation both into and out of the can.

Several difficulties attend thelancing method. The coating material tends to be applied to the wall of the can in a helical path which often results in helical streaks along the can wall. Other problems occur in timing the spray with the movement of the lance. In particular, it is difficult to cut off the flow of coating material at the precise instant that the spray begins to be projected outside the open end of the can as the lance emerges therefrom while supplying a sufficiently thick coating to the can wall adjacent the open end. Overspray tends to be excessive and consequently, maintenance and repair of the reciprocating device and related mechanism is often required at frequent intervals. Finally, the lancing method is quite inefficient in that considerable time is required to move the lance into the can and to withdraw it therefrom.

SUMMARY OF THE INVENTION A general object of our invention is to provide a nozzle particularly suited for spraying the interiors of hollow cylindrical bodies such as cans having one end open which substantially eliminates the disadvantages described above which have been encountered with prior can spraying apparatus.

, Another object is to provide a spray nozzle particularly for spraying the interiors of cans having one closed end that provides a more uniform film distribution, particularly over the closed end and adjacent juncture with the side of the can.

Another object of our invention is to provide outlet orifices having such form and contour in an airless spray nozzle as to give asymmetrical spray patterns selectively related to the relative length and diameter of a can to be coated tending to provide a uniform coating over the entire interior of a can having one closed end. Such a pattern preferably gives a maximum flow between one end and the middle of the pattern with smooth gradations from the point of maximum flow to each end, and an object of our invention is to provide nozzles that will produce spray patterns which will deposit paint uniformly on the sides and ends of a can in substantial proportion to the relative areas thereof.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a plan view of the orifice of one form of our controlled distribution nozzle.

FIG. 2 is a longitudinal, vertical as viewed, section of the body of the nozzle of FIG. 1, taken in the plane of the line 2-2 of FIG. 1 showing a first cut toward making the nozzle orifice.

FIG. 2a corresponds to FIG. 2, showing however, the second cut independently of the first cut to illustrate making the nozzle orifice.

FIG. 1a is a view corresponding to FIG. 1 showing the first cut only toward making the nozzle orifice.

FIG. 1b is a view corresponding to FIGS. 1 and la I showing however the second cut of making the nozzle orifice, independently however for illustration, of the first cut.

FIG. 3 is a fragmentary view of the cutting edge of one of the wheels for making the first cut of the orifice shown in FIGS. 1, 1a and 2.

FIG. 4 is a fragmentary view of the cutting edge of the other wheel for cutting the other part of the orifice I shown in FIGS. 1, lb and 2a.

FIG. 5 is a plan view of the orifice of a preferred form of our controlled distribution nozzle.

FIG. 6 is a longitudinal, vertical as viewed, section of the body of the nozzle of FIG. 5 taken in the plane of FIG. 10 shows the known spray pattern of prior art drumhead nozzles in which the place of maximum flow is at or closely adjacent the one end of the pattern and the place of minimum flow at the other end.

FIG. 11 is a plan view of the orifice of another preferred form of our controlled distribution nozzle.

FIG. 12 is a longitudinal, vertical as viewed, section of the body of the nozzle of FIG. 11 taken in the plane of the line 12-12 of the axis of the nozzle.

FIG. 13 is a view corresponding to FIG. 11, but showing the configuration or nominal configuration of both FIG. 15 is a fragmentary view of the cutting edge of v the wheel for making the broader cut or gash.

FIG. 16 is substantially a mirror view of FIG. 8 showing the reversed, right to left, pattern of our controlled distribution nozzle of FIG. 11.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A. The Controlled Distribution Nozzle Illustrative and preferred embodiments of our airless spray nozzle orifices for controlled selective distribution spray patterns, are shown in FIGS. 1, 5 and 11 in their final form. The figures related to FIGS. 1, 5 and 11 depict the nozzles at various stages of cutting of the nozzle orifices. It is a purpose of these nozzles to produce flat, fan-shaped airless spray patterns having a predetermined distribution which will match ideally with the internal surface configuration of a can or other hollow body, with a closed end to apply a uniform coating thcreover.

In the spray pattern of the controlled distribution nozzle, as shown in FIG. 8, the maximum flow of paint, or coating material, occurs at a point 10 approximately percent distant from the far end of the fan F and 25 percent from the near end. Reasonable tolerances within good commercial practice are i 5 percent. The amount of material flowing in the rest of the fan tapers smoothly and substantially linearly from the point of maximum flow 10, to points of minimum flow at each end of the fan. In contrast, the prior art drumhead nozzle, FIG. 9, produced the familiar fan pattern, FIG 10 with maximum flow at the point 11 at or quite closely adjacent one end of the pattern and tapering linearly to minimum flow at the other end; substantially in a 5 percent flow distribution.

B. First Nozzle Embodiment An illustrative embodiment of a controlled distribution nozzle adapted to produce a spray pattern with a distribution similar to FIG. 8, is illustrated in FIG. 1, and comprises an orifice O slashed or cut in the top as viewed, of the hollow cylindrical body B, the work piece until completed, FIGS. 2 and 2a, with an internal cylindrical approach passage P terminating in the plane 36, its upper end in the base circle, or ellipse, of a substantially hemispherical internal dome D. The wall of body B is, for convenient illustration, shown to be of substantially uniform thickness over and about the dome. The orifice O is of size, shape andposition tending to yield a distribution profile similar to FIG. 8, and is cut into the dome D by two rotary cutting wheels, W and W having different cutting angles, i.e., different degrees of peripheral sharpness, FIGS. 3 and 4. The

wheels may have appropriate known qualities for coping with the material of the nozzle tip.

A first rotary cutter, such as a diamond charged wheel W, FIG. 3, and see FIG. 1a, for cutting tungsten carbide, is narrowly tapered with an included angle of about 22% at and comprising the cutting edge. It may have a radius R of 3 inches, for example, to cut the narrow, leftward, as viewed, part 0 of orifice 0, FIGS. 1, 1a and 2. The wheel W has its center angled leftwardly from the longitudinal axis aa of the body B, and cuts an inclined tapered gash along and down to the line 37 through the wall of the body above and adjacent the dome D down to the leftward point x at the base circle of the dome and down to the point x above the base circle on the right side of the dome as shown in FIGS. and 2. The line of the bottom of the cut 37 is angled to the base of the dome and the inclined aspect of the wheel to the axis aa of the passage P being for this example 7% as shown.

In this illustration the movement of the wheel W, as well as W discussed below, will be in the plane 2-2 of the axis aa. A 3-inch wheel cutting an orifice 0.015 inches long, for example, will have a substantially straight line 37 for the bottom of the cut even if the bodily movement of the center of the wheel advances the wheel only along its radius R on the line 45, 41, 43 inclined at said 7% to the axis aa. The line 45-43 is the perpendicular bisector of the line 37 between the points x and x and passes through the center of the base circle of the dome, i.e., the intersection of aa and plane 36 normal thereto. The same cut may be made with inclined rightward and leftward bodily movement of the wheel so long as the 7 k inclined aspect of the wheel to the work is preserved.

In this illustration the cuts or gashes made by the wheels W and W respectively, are shown in FIGS. 2, 2a, 1a and lb as if each were a first cut. In practice the cuts are made successively so the second cut is made in part in the void of the first cut and is more awkward to explain in the first instance than the friction of each cut being first and original. In FIGS. 1, 1a and 1b the circle, or ellipse of the base of the dome is suggested in dotted lines. As shown in FIG. 2, the line 37 intersects the outside of the body at points 39 and 49 which define theends of the gash in the exterior of the body. Points 45 and 41 show the places of greatest width of the cut at the outside and inside, respectively, of the wall of the dome, and are offset from the axis by distances 44 and 40 respectively. Vertical projections of points 41 and 45 intersect the diameter of the base of the dome in points 42 and 46 respectively. The equivalent of points 41, 43 and 45 in the wheel W when cutting at full depth on the line 37 are shown at points 41a, 43a and 45a respectively in the wheel whereby to visualize the maximum widths 48 and 47 of the gash in the exterior and interior of the wall of the dome. These lines of width are transposed to FIG. 1a passing through the points 46 and 42 respectively and show the effect of tipping the gash and moving the places of maximum width leftwardly of the axis aa. As seen in FIG. 1, this leftward inclination of 0' makes the widest part of it join the gash a", FIG. lb, more harmoniously than were the line 37 to lie in the plane 36. This also results in a smoother line from the point 10 in FIG. 8 to the left end of the spray pattern. This inclination of the line 37 tends in minor degree to move the point 10 leftward in the spray pattern, of FIG. 8.

A second cutting wheel W of greater included angle of taper in the cutting edge, taken arbitrarily at 50 for this illustration, and radius R, FIG. 2 equal to R has its center offset rightwardly from the axis aa of body B, and cuts a broader rightward gash 0" through the dome, the bottom line 61 of which is inclined at 30, also taken arbitrarily, to the axis and plane 36. Wheel W' cuts through the wall above and about the dome D down to the point y on the right of the base circle of the dome diametrically opposite the point x. This puts the ends of the exterior of the cut at the points 59 and 60 as shown in FIGS. 2a and 1b, and puts the actual and tentative ends of the part 0" of the orifice O at the points y and y in the surface of the dome. When this is literally a second cut, the points y and 59 will lie in the void of the leftward part of the first cut. Following the procedure used above, the perpendicular bisector of the part y'y of the line 60 originates at point 53 and passes through the intersection of the axis and plane 36 and the points 51 and in the dome and external wall above it. These points are offset distances 50 and 54 respectively from the axis and project downwardly to points 52 and y in the diameter of the base of the dome. Transposition of corresponding points 53a, 51a and 55a in the wheel W, FIG. 4, permits the measurement of maximum width of the cut in the dome and in the wall above it at lines 57 and 58, the transposition of which to FIG. 1b depicts the whole cut and orifice containing the part 0 in plan view, as if the cut were made through solid material in the first instance. It remains merely to superpose FlGSQla and 1b to show the effect of the successive steps and cuts to make the composite orifice O and the exposed surfaces of the cut in the wall above and about the dome. The orifice O has sharp cuts at both ends, particularly the right, as viewed, end which distinguishes it radically from the prior drumhead nozzles, and provides smoothly curved lines joining the place of maximum flow, corresponding to the point 10, to the ends of the pattern. The line 57 of greatest width of the orifice 0 corresponds approximately with the place of greatest flow in the pattern, and by its length and offset from the axis aa plays the major part in placing the point of maximum flow, like point 10, where it may be desired in the spray pattern.

In FIG. 8, the oval area F at the top of the pattern is the place or target of impact of the .fan F with the corrugated sheet or substrate. The point 10 lies at the bottom of the longest line offlow of paintfrom the oval and shows the whereabouts in the spray fan of maximum flow. The lesser lines of flow'of paint from different parts of the oval down the sheet measure the relatively lesser quantities of paint in corresponding parts of the fan. We have called the part H of the pattern to the left of the line of point 10 the heavy part, and the part L to the right, the light orlighter part. This is convenient in respect to relating the different parts of the pattern to different parts of the can or hollow body being painted. This explanation is made to avoid confusion between one usage and the logical description of the heavy part of the pattern as that containing the maximum flow. In our usage we speak of the line or path of maximum flow as the line of division between parts I] and L, or as an appreciable part of the pattern comprising the great flow to the point 10, as the context will suggest.

The following description of our two preferred forms of nozzle orifices will exemplify different advantageous ways of following the principle while altering the form of the orifice described above. Preliminarily, it will be evident from the discussion about the orifice O that reducing the inclination of the line 60 from 30 to 20 about the point y, for example, that the wide cut from the wheel W will be extended leftward, tending to move the point 10 leftward in the fan pattern, and increasing the light part L of the pattern at the expense of the heavy part H. This will also tend to lengthen the cusp up from the point y and improve the quality of distribution in the part L of the pattern. Foreshadowing our preferred orifice in FIG. 11 (which is turned right or left from FIGS. 1 and 5), our teaching includes changing the depth as well as the inclination of any cut through the dome; specifically raising and/or tipping the bottom line 60 of the cut, to diminish the size and effect of 0" in relation to 0' in the orifice O.

C. The First Preferred Nozzle A first preferred embodiment of our controlled distribution, or controlled pattern, nozzle is shown in FIGS. 5, 6 and 7, and differs from the embodiment described above in both the shape of the discharge orifice and in the method of cutting it. As shown in FIG. 5, the orifice O0 is approximately tulip-shaped, or arrowheadshaped, comprising two minor divergent cusped lobes 23 and 24 on the right as viewed, side of the axis a-a of nozzle body B which merge into a major cusped lobe that terminates at the point x, see also FIGS. 6 and 7, on the opposite side of axis aa. The lobes 23 and 24 join at the point 34, or line 34-35, diametrically opposite the point x but higher on the curve of the dome from the base thereof, FIGS. 5 and 6. The section of maximum width 28 of the orifice lies near the point 34 substantially in a plane at right angles to the plane containing the axis and points x, 34 and 35. Approximately 25 percent of the coating material output from the orifree 00 appears to emerge from lobes 23 and 24 while about 75 percent of the material appears to emerge from the remaining portion of the orifice to form the spray pattern of FIG. 8.

The tulip or arrowhead orifice 00, FIG. 5 is preferably cut and formed as shown in FIGS. 6 and 7 by the cutting wheel W2 making two chordal gashes down to the base circle of the dome; both gashes passing through the point x on the left, as viewed, with one passing through the point y and the other through y on the right side of the base circle of the dome. The first cut is shown in full; the second in dotted lines in FIG. 7. The bottom of the first cut and the intersection of the central plane thereof with the plane of the base circle of the dome follows the imaginary line K, FIG. 7, at the angle 0 from the central longitudinal plane 6-6 of the body B. After the first cut is made the work piece, i.e., the unfinished body B, is rotated relative to the wheel W about a line parallel to axis a-a and passing through the point 1: so that the second cut will follow the line Q at an equal and opposite angle c on the opposite side of the central plane 6-6. The second cut is shown in dotted lines; the two gashes together form the arrowhead orifice 00, FIG. 5. The finished orifice 00 has major sloping side surfaces 30 and 31 and minor side surfaces 32 and 33 which lie on opposite sides of the uncut wedgelike part 38 of the wall of the dome. The surfaces 32 and 33 intersect in the line 34-35 in the plane 66, FIG. 7. It will be appreciated that when the lines K and Q coincide a simple symmetrical pattern will result and the point like of maximum flow will be shifted to the middle of the pattern. Conversely as the angle of divergence 2c between lines K and Q increases, the point of maximum flow will be moved more nearly to the right, as viewed, in FIG. 8, of the pattern. Presently we have not tested the advantageous limits of such divergence beyond shifting the point 10 to about an 85 15 percent pattern.

An example of a controlled distribution nozzle formed in this manner has an orifice of about 0.015 inches equivalent diameter and projects a fan spray having an output rate of flow of water of about 120 cc per minute at about 40 psi. The width of the fan-shaped spray pattern produced by this orifice is approximately 8-10 inches measured normal to the nozzle axis at about 10 inches from the nozzle to the target. The cutting edge of wheel W is tapered at an included angle of about 25, and has a radius of 3 inches. Angle c in FIG. 7 is approximately 8%.

D. The Second Preferred Nozzle This preferred form of our nozzle invention and method of making an embodiment thereof is illustrated in FIGS. 11-15. An illustrative spray pattern from this nozzle is shown in FIG. 16, which is a mirror view of FIG. 8. The orifice 0 FIG. 11, is a composite resulting from two successive cuts made by two different wheels W and W FIGS. 14 and 15, both moving in the central longitudinal plane 1212 and making cuts of different inclination, breadth and depth.

As shown in FIGS. 12 and 14, and in full lines in FIG. 13, this first cut is quite conventional and made with the wheel W having a cutting edge with faces inclined at a 37 included angle, down to the line in plane 36 of the base of the dome at the orthodox points x and y. Such a cut would givea conventional symmetrical fan pattern as if the point 10 were in the middle. The center of wheel W is aligned with the axis a-a of the dome D, approach passage P and nozzle body B, so the line 70 is horizontal and the perpendicular bisector of x-y coincides with the axis a-a. The widest part of the cut through the dome is suggested at and through the outer wall at 76, FIG. 12, and translates to lines 75b and 76b taken through the wheel W3 at points 75a and 76a,,corresponding points 75 and 76 in the work, and to the cut as viewed in plan and seen in full lines in FIG. 13. The line 70 of the first cut crosses the axis a-a at point 72, FIG. 12, as suggested at the point 72a at the extreme edge of the wheel, FIG. 14.

The second out has the office and function of moving the line or path of greatest flow in the spray pattern from the middle leftwardly as viewed in FIG. 16 over to about the quarter point about midway between the center and left end of the. pattern and giving the light side L about 25 percent and the heavy side I-I about 75 percent of the flow of paint. This second cut is made with the wide (1 15) angle cutting edge wheel W.,, FIG. 15, inclined along line 71 at l6 k to the plane 36 and line 70 with the center of the wheel angled 16% from axis a-a when it coincides with the perpendicular bisector 72-74 of the part 77-79 of line 71 where the latter intersects the hemisphere of the dome, actually in the void in the first cut. The bottom of the second cut at its greatest depth reaches only about 40 percent of the way down the radius 72-73 of the dome whence the extreme ends of the first cut in the plane 36, FIGS. 11, 12 and 13, are untouched by the wheel W and their narrow sharp cusped ends persist in their benign influence at and within the edges of the parts H and L of the spray pattern.

Projecting the points 77, 74, 73, 79 and the intersection of line 71 with the outside of the wall of the dome down in the plane 12-12 to the diametric line x-y and 70, the respective points 87, 84, 83, 89 and 71a are established to locate these points in plan view in FIGS. 11 and 13. The projection of the intersection of line 71 with the left interior surface of the dome is substantially coincident with the intersection of the line 70 with the same surface. These projected points locate the ends and places of greatest width of the orifice and gash cut by the wheel W The respective widths are found, as above, by translating the points 73 and 74 into the wheel at points 73a and 74a; the point 78a translating extreme edge of the wheel contacting the point 78. At the points 73a and 74a in the wheel, the width thereof, which reflects the maximum width of the orifice and gash is shown in lines 73b and 74b, and translating these lines into FIG. 13 establishes the plan view of the outline, shown in dotted lines, of the gash through the wall above the dome and the orifice in the dome.

As shown in FIGS. 11 and 13, the bluntness of the wheel W. make the gash, and orifice cut thereby, al-

most as wide as long and loses the theoretical ends of the orifice in the void of the first cut. In FIG. 11, the dominance of the part 91, of the final orifice 0 made by the wheel W is shown relative to the part 90 cut by the wheel W in the right part of orifice O and a small part of the orifice and gash cut by the wheel W at the left end of the orifice 0 FIGS. 11 and 13.

Our present tests and observation of nozzles having the orifice 0 appear to show that their orifice can give much the same pattern, FIG. 16, as the nozzle 00, FIG. 8, when the place of maximum flow, point 10, is midway between the middle and the near end of the pattern. The nozzle 0 presently appears to be more predictable in respect to its pattern as the second cut is inclined, and/or cut more deeply, to move the point 10 of the pattern nearer the end of the pattern. Conversely reducing the inclination of the second cut, as from 16% to 13 will tend to move the point 10 of the pattern toward the middle, reducing H and increasing L.

A method of coating single open end cans that may advantageously employ the nozzle of this invention is described and claimed in our copending application Ser. No. 13,598 referred to above.

While we have illustrated and described exemplary and preferred forms of our invention, changes and improvements will occur to those skilled in the art who understand its advantages and uses, and we do not want to be limited to the embodiments and examples specifically disclosed herein, nor in any manner inconsistent with the progress by whichwe have promoted the art.

What is claimed is:

1. A spray nozzle for spraying an asymmetrical pattern with the place of maximum flow located between about the middle and one end of the pattern and with smoothly reduced flow between the place of maximum flow and each end of the pattern, comprising a hollow body having a central axis, an approach passage terminating in a substantially hemispherical dome having a substantially circular base circle, said dome and the wall exterior thereof being slashed to form the discharge orifice, said orifice having a sharp pointed terminal at each end, and having spaced apart lines of intersection with said dome between said ends, and having an asymmetrically disposed place of maximum openingbetween said lines located between the middle and one end of said orifice corresponding approximately to said place of maximum flow in said pattern.

2. The nozzle of claim 1 wherein said orifice has one terminal at one side of said dome and has two terminals at the other side of said dome spaced circumferentially from each other and has a wedge-like part of the wall of the dome intruding into said orifice at said other side.

3. The nozzle of claim 2 wherein said terminals lie in approximately the base circle of the dome.

4. The nozzle of claim 2 with said wedge-like intruding part having a pointed end at about said place of maximum opening of said orifice.

5. The nozzle of claim 1 wherein said orifice has one pointed terminal at each end and said spaced apart lines of intersection have changes in curvature near said place of maximum opening; the lines from said place to said one end having an appreciably smaller radius of curvature than the radius of curvature of the lines from said place to the other end of said orificeJ 6. The nozzle of claim 5 wherein the parts of said orifice between said lines of different radii of curvature are inclined at different angles to the base circle of said dome.

7. The nozzle of claim 5 wherein the parts of said orifice between said lines of different radii of curvature are unequally related to the base circle of the dome.

8. The nozzle of claim 7 wherein said parts of said orifice are unequally spaced from the point of intersection of the axis of said passage and said base circle of the dome.

9. The nozzle of claim 1 wherein said terminals lie substantially in said base circle of said dome, and said place of maximum opening comprises a part of said orifice cut more remotely from the intersection of said axis with said base circle than the rest of said orifice.

10. A spray nozzle for spraying an asymmetrical pattern with the place, of maximum flow located more nearly a quarter point of the pattern than either the middle or the end thereof and with smooth gradations from said place to the ends of the pattern, comprising a hollow body having a domed blind end with rounded base and a central axisintersecting the plane of said base, said dome having a plurality of superposed orifices of different shapes slashed therethrough resulting in a composite orifice with a distinctive part of maximum opening spaced from said axis on one side thereof and cusped placesof minimum opening at the ends thereof. 

1. A spray nozzle for spraying an asymmetrical pattern with the place of maximum flow located between about the middle and one end of the pattern and with smoothly reduced flow between the place of maximum flow and each end of the pattern, comprising a hollow body having a central axis, an approach passage terminating in a substantially hemispherical dome having a substantially circular base circle, said dome and the wall exterior thereof being slashed to form the discharge orifice, said orifice having a sharp pointed terminal at each end, and having spaced apart lines of intersection with said dome between said ends, and having an asymmetrically disposed place of maximum opening between said lines located between the middle and one end of said orifice corresponding approximately to said place of maximum flow in said pattern.
 2. The nozzle of claim 1 wherein said orifice has one terminal at one side of said dome and has two terminals at the other side of said dome spaced circumferentially from each other and has a wedge-like part of the wall of the dome intruding into said orifice at said other side.
 3. The nozzle of claim 2 wherein said terminals lie in approximately the base circle of the dome.
 4. The nozzle of claim 2 with said wedge-like intruding part having a pointed end at about said place of maximum opening of said orifice.
 5. The nozzle of claim 1 wherein said orifice has one pointed terminal at each end and said spaced apart lines of intersection have changes in curvature near said place of maximum opening; the lines from said place to said one end having an appreciably smaller radius of curvature than the radius of curvature of the lines from said place to the other end of said orifice.
 6. The nozzle of claim 5 wherein the parts of said orifice between said lines of different radii of curvature are inclined at different angles to the base circle of said dome.
 7. The nozzle of claim 5 wherein the parts of said orifice between said lines of different radii of curvature are unequally related to the base circle of the dome.
 8. The nozzle of claim 7 wherein said parts of said orifice are unequally spaced from the point of intersection of the axis of said passage and said base circle of the dome.
 9. The nozzle of claim 1 wherein said terminals lie substantially in said base circle of said dome, and said place of maximum opening comprises a part of said orifice cut more remotely from the intersection of said axis with said base circle than the rest of said orifice.
 10. A spray nozzle for spraying an asymmetrical pattern with the place of maximum flow located more nearly a quarter point of the pattern than either the middle or the end thereof and with smooth gradations from said place to the ends of the pattern, comprising a hollow body having a domed blind end with rounded base and a central axis intersecting the plane of said base, said dome having a plurality of superposed orifices of different shapes slashed therethrough resulting in a composite orifice with a distinctive part of maximum opening spaced from said axis on one side thereof and cusped places of minimum opening at the ends thereof. 